KR20010089415A - Thermoplastic resins stabilized by blends of sterically hindered phenols, secondary amines, and thioethers - Google Patents

Abstract

A method is disclosed for stabilizing a thermoplastic resin, which may also contain carbon black and/or glass, wherein the method comprises adding to the resin a stabilizing amount of at least one sterically hindered phenol antioxidant, at least one secondary amine antioxidant and/or at least one N,N'-substituted oxamide antioxidant, and at least one thioether antioxidant.

Description

Thermoplastic resins stabilized by blends of sterically hindered phenols, secondary amines, and thioethers

The manufacture of plastic products has been a long lasting problem in stabilizing plastic resins during the high temperature, high shear, mixing and extrusion processes that are common in the industry. Resins that exhibit good long term thermal stability properties may not be sufficiently protected against the type of degradation that occurs during long residence times in extruders or when glass mat reinforced thermoplastics (GMT) applications in which plastics are exposed to high temperature heat fusion followed by compression molding. .

GMT is a rapidly growing area in the automotive sector under hood applications. Due to very poor process conditions in manufacturing GMT, the requirements for stabilizing thermoplastics, as set by the GMT producer, are enormously high. For example, GMT test specimens containing viable antioxidant candidates must pass long term thermal aging tests at 150 ° C. for 1000 hours. In the second test, the GMT test specimens should show a loss of 2% by weight or less after 15 minutes of exposure at 230 ° C. Commercially available antioxidants can provide this type of stabilizing effect but are economically impractical because they are only available at excessively high load levels. Accordingly, there is a continuing need to develop new antioxidants or mixtures thereof that can provide the required stabilization at load levels lower than those currently known.

European Patent Publication No. 0 080 409 discloses epichlorohydrin polymers (100 parts), plasticizers (0.5 to 20 parts), reinforcing fillers (1 to 150 parts), useful in molding bags resistant to oil at 140 ° / skbar, Rubber compounds containing metal stearates (0.5 to 7.5 parts), Pb ₃ O ₄ (0.5 to 7.5 parts), stabilizers (0.5 to 5.5 parts) and vulcanizing agents (0.5 to 5.5 parts) are described. Thus, 100 parts of polyepichlorohydrin, 4 parts of stearic acid, 2.5 parts of Pb ₃ O ₄ , 1 part of zinc stearate, 2.5 parts of N-isopropyl-N'-phenyl-p-phenylenediamine, (Bu ₂ NCS ₂ ) A mixture of 1 part ₂ Ni, 0.75 parts H ₂ N (CH ₂ ) ₆ COOH and 30 parts carbon black was vulcanized at 160 ° for 40 minutes to yield a tensile strength of 18.7 MPa, elongation 900%, 300% modulus 6 MPa and shore strength Obtaining a rubber having 61; Rubber having a tensile strength of 16.3 MPa, elongation 720%, 300% modulus 7.6 MPa and Shore strength 64 after 24 hours in 140 ° air; Compared to a rubber with a tensile strength of 14.3 MPa, elongation 500%, 300% modulus 9 MPa and Shore strength 60 after 24 hours in 140 ° oil.

U.S. Patent 4,797,511 discloses polyolefins, carbon black homogeneously incorporated into the polyolefins, stabilized amounts of thiodiethylene bis (3,5-di-t-butyl-4-hydroxy) hydrocinnamate (Naugard 35 or EL50), A para-substituted aralkyl-substituted diphenylamine incorporated into the polyolefin and a first stabilizer component incorporated into the polyolefin; A composition stabilized against oxidative degradation comprising a second stabilizer component of at least one amine antioxidant selected from the group consisting of para-phenylenediamine and polymerized dihydroquinoline is described.

U.S. Patent No. 4,837,259 discloses (a) at least one aralkyl-substituted diarylamine; And (b) polypropylene stabilized against oxidative degradation by the presence of a stabilizing amount of an antioxidant composition comprising at least one sterically hindered phenol.

The stabilizing effect of these mixtures is illustrated by the preservation of the melt-flow rate and the measurement of Hunter color values. However, the patentee clearly explains the effect of stabilization of the mixture by measuring the preservation of the melt-flow rate and color retention of the stabilized resin, while the stabilization demonstrated by the oven aging test, the most critical test method used in the GMT industry, is described. Did not do it. The inventors have tested the mixtures within this patent category for oven aging stability and found that polypropylene films stabilized with the corresponding mixtures of diarylamines and sterically hindered phenols are produced in 200 hours at 150 ° C., much shorter than the 1,000 hour GMT requirement. Found.

European Patent Publication No. 0 328 788 discloses 100 parts by weight (pbw) of aromatic vinyl compound-conjugated diene block copolymers and mixtures of 1.0 to 5.0 pbw of two or more compounds selected from dithiocarbamate derivatives, triazine derivatives and polyphenol compounds. A composition comprising, an adhesive composition containing the same, and a method for preparing the compositions by mixing the components are described.

Japanese Patent No. 71037440 discloses thiourea, Irganox RA-565, Soxinol PZ {(Me ₂ NCS ₂ ) ₂ Zn as discoloration stabilizer for polypropylene fibers and films containing phenolic antioxidants. } (Soxinol PZ {(Me ₂ NCS ₂ ) ₂ Zn}), Aganox RA-1093 and Soxynol M (2-mercaptobenzothiazole) are described. For example, a polypropylene fabric containing 0.25% aganox RA-1010 and impregnated with a 5 g / l thiourea solution (wet pick up 80%) is not discolored by ammonia, while the unfinished fabric becomes pink. .

Hwahak Kwa Hwahak Kongop (1975), 18 (6), 302-9 disclose tetraethylthiuram disulfide (I) and tetramethylthiuram disulfide (II) as heat stabilizers for S-modified neoprene rubbers. The use of is described. As the contents of I and II increased, the scorch time increased proportionally, Ni bis (N, N-dibutyl dithiocarbamate) (III), N-phenyl-2-naphthylamine (IV ), Thiophenylamine (V) and BHT accelerate crosslinking. III, IV and V are good antioxidants and inhibit dehydrochlorination. Rubbers containing 1% of I have a shelf life of 1.5 years (70% reduction in plasticity).

WO 95/25074 discloses aqueous chemical treatments or sizes for siliceous fibers and fillers having polyolefin compatible film-forming polymers, organic-functional coupling agents and at least one stabilizer for producing polyolefin reinforced products. Is described. Stabilizers include at least one of alkali metals and alkaline earth metals and ammonium, phosphinates, phosphites, hipphosphites, sulfites and bisulfites, organic phosphinates and / or phosphites and mixtures thereof, and hindered phenols ( Used in combination with other types of antioxidants such as hindered phenol), diaryl amines and thioethers, the amount of stabilizer is an effective stabilizing amount. Optionally the size may have one or more partial esters of branched carboxylic acid copolymers present.

U. S. Patent No. 5,646, 207 describes aqueous sizing compositions for glass fibers which are said to be particularly useful for the reinforcement of thermoplastic or thermoset matrix polymers containing film-forming materials, fluorescent whitening agents, coupling agents, stabilizers and lubricants. The film-forming material is chosen to be compatible with the thermoset or thermoplastic matrix polymer used in the ultimate forming process. Fluorescent whitening agents are at least dispersed, emulsified or dissolved in water.

Said sizing composition is said to be particularly advantageous for sizing glass fibers that can be used to reinforce the matrix polymer for forming molded parts. The molded parts obtained show exceptional whitening and show comparable physical properties to the material without polish.

Gachter / Muller: Plastics Additives Handbook, Hanser Publisher, 4th ed. Describes the antioxidant properties of sterically hindered phenols, diarylamines, and thioethers, but not ternary mixtures. See in particular pages 40, 41, 44-47 and 52-55. "The most important long-term heat stabilizers for polypropylene are medium molecular weight phenols (300-600), especially high molecular weight phenols (600-1200). They are often synergists, for example dilauryl tea. Used with thioethers such as odypropionate ..., or distearyl thiodipropionate ..., or dioctadecyl disulfide ... ".

The disclosures of which are incorporated herein by reference in their entirety.

The present invention relates to the oxidation stabilization of thermoplastics, in particular polyolefin-based thermoplastics.

The present invention features a polymeric material comprising a stabilizing mixture of at least three components. The first component is a hindered phenol, the other component is a secondary amine and / or one or more N, N'-substituted oxamides and another component is a thioether.

More specifically, US Pat. No. 4,837,259 has shown that oven aging stabilization of secondary amine / phenol mixtures can be improved when additional components selected from thioethers are included, thus ternary or quaternary mixtures Is given. For example, oven aging performance after addition of distearylthiodipropionate typically improves from about 200 hours to about 1,000 hours, a fivefold increase.

More specifically, the present invention relates to a composition comprising the following components (A) to (B).

(A) thermoplastic resin; And

(B) Stabilization amount of at least one sterically hindered phenol antioxidant, at least one secondary amine antioxidant and / or at least one N, N'-substituted oxamide, and at least one thioether antioxidant mixture.

In a preferred embodiment, the invention relates to a composition comprising the following components (A) to (D).

(A) thermoplastic resin;

(B) up to 10% by weight carbon black;

(C) up to 50% glass; And

(D) Stabilization amount of following (1)-(3):

(1) at least one member selected from the group consisting of

With N, N'-substituted oxamides and / or one or more secondary amine antioxidants

A first stabilizer made up;

(Iii) hydrocarbon-substituted diarylamines,

(Ii) reaction products of diarylamines and aliphatic ketones,

(Iii) N, N'-hydrocarbon substituted para-phenylenediamine, and

(Iii) polymerized dihydroquinoline;

(2) a second stable consisting of at least one hindered phenolic antioxidant

issue; And

(3) A third stabilizer consisting of at least one thioether antioxidant.

In another aspect, the present invention provides a composition comprising a thermoplastic resin comprising at least one sterically hindered phenolic antioxidant, at least one secondary amine antioxidant and / or at least one N, N'-substituted oxamide antioxidant, and A method for stabilizing said composition consisting of adding a stabilizing amount of at least one thioether antioxidant.

In a preferred embodiment of this aspect, the present invention relates to stabilizing amounts of the following components (A) to (C) in a composition consisting of a thermoplastic resin, up to 10% by weight carbon black, and up to 50% by weight for oxidative degradation. It relates to a method of stabilizing the composition consisting of adding.

(A) at least one N, N'-substituted selected from the group consisting of the following (1) to (4)

Oxamide antioxidant and / or one or more secondary amine antioxidants

First stabilizer;

(1) hydrocarbon-substituted diarylamines,

(2) reaction products of diarylamines and aliphatic ketones,

(3) N, N'-hydrocarbon substituted para-phenylenediamine, and

(4) polymerized dihydroquinoline;

(B) a second stabilizer consisting of one or more sterically hindered phenolic antioxidants; And

(C) Third stabilizer consisting of at least one thioether antioxidant.

Description of the Preferred Embodiments

The invention features a polymeric material to which a stabilizing mixture of at least three components is added. The polymerizable material provided with stabilization by the stabilizing mixture of the present invention is selected from the group of thermoplastics, in particular polyolefins, preferably polypropylene. Further included are certain inorganic fillers, such as glass, added up to about 50% of the total weight of the glass and resin.

Another preferred embodiment of the present invention includes carbon black present in the polymer or glass filled polymer. Carbon black is useful, among other things, to provide resistance to the effects of ultraviolet radiation.

Thermoplastic resins that can be stabilized against oxidative degradation using ternary mixtures of the present invention are low density polyethylene (LDPE), linear low density polyethylene (LLDPE), medium density polyethylene (MDPE), high density polyethylene (HDPE) or 0.85 to 1.4 gm / Resins derived from ethylene, including other ethylene derived resins having a density of cm 3; Homer polymers derived from C ₃ and higher mono- and di-ethylenically unsaturated hydrocarbon monomers such as polypropylene, polyisobutylene, polymethylbutene-1, polymethylpentene-1, polybutene-1 Polyisobutylene etc .; Copolymers derived from two or more monomers such as ethylene-propylene copolymers having at least the majority of propylene, propylene-butene-1 copolymers, propylene-isobutylene copolymers and the like and mixtures thereof; polystyrene; Polyvinyl halides; And engineering thermoplastics such as polyamides, polyesters, polyphenyleneoxides, polyphenylenesulfides, polyacetals, aliphatic polyketone copolymers or terpolymers, poly (ethersulfones), polycarbonates, liquid crystals Polymers, poly (etheretherketones), and poly (allylates). The thermoplastic resin protected by the stabilizing mixture of the present invention is preferably a polyolefin resin, most preferably polypropylene.

As mentioned above, one of the components in the stabilizing mixture included in the thermoplastic resin, which may or may not include glass and / or carbon black, is a hindered phenol. Other components are secondary amines and / or N, N'-substituted oxamides. Another component is selected from the group consisting of thioethers. Mixtures of these hindered phenols, oxamides / secondary amines, and thioethers are optionally thermoplastic resins in the presence of carbon black and / or glass, as evidenced by oven aging tests, weight loss measurements, and extended oxidative induction time. For example, it has unexpectedly been found to protect polypropylene from polymer breakage.

The stabilizing composition of the present invention is useful for stabilizing thermoplastics, but particularly for stabilizing thermoplastics, including carbon black. This is especially useful because many stabilizers useful for protecting resins that do not contain carbon black are known in the art that their usefulness is lost when carbon black is added. This phenomenon is reported in Hawkins, WL in Polymer Degradation and Stabilization , Springer-Verlag, New York (1984). In particular, referring to page 56, it states:

Arguments between antioxidants are expected when interactions occur that destroy or diminish the efficacy of either component. Hakins and coworkers have observed that when carbon black used to protect against outdoor weathering is used with secondary amines or certain hindered phenols, antagonistic effects are observed.

Carbon black is a weak thermal antioxidant for polyethylene at 140 ° C. which, when used alone, inhibits oxidation for only about 20 hours. On the other hand, amines provide an effective protective effect for more than 450 hours. However, when the two are used together, the polymer is only protected for about 100 hours. In addition, carbon black reacts counterproductively with many hindered phenols.

Adsorption of amines or phenols on carbon black surfaces has been proposed as an explanation for the anti-wood effect. However, the range of antagonisms is diversified by the chemical structure of carbon black, suggesting that catalytic destruction of antioxidants on the surface can be a major responsible factor for antagonism. There are also phenols that show a synergistic effect with carbon black over antagonism.

It was further found that the stabilizing three-component mixture may consist of two components selected from secondary amines and / or N, N'-substituted oxamides and one component selected from thioethers, provided that the secondary One of the amines / oxamides contains hindered phenol functionality. Thus, in the practice of the present invention, at least three separate components must be present, one component having secondary amine and / or N, N'-substituted oxamide functionality, and one component having a hindered phenol function. And one component must have thioether functionality.

The hindered phenols useful in the practice of the present invention are preferably selected from the group consisting of hindered phenols having a molecular weight of 500 Da or more. Preferred examples include 2,4-dimethyl-6-octyl-phenol; 2,6-di-t-butyl-4-methyl phenol (eg butylated hydroxy toluene); 2,6-di-t-butyl-4-ethyl phenol; 2,6-di-t-butyl-4-n-butyl phenol; 2,2'-methylenebis (4-methyl-6-t-butyl phenol); 2,2'-methylenebis (4-ethyl-6-t-butyl phenol); 2,4-dimethyl-6-t-butyl phenol; 4-hydroxymethyl-2,6-di-t-butyl phenol; n-octadecyl-beta (3,5-di-t-butyl-4-hydroxyphenyl) propionate; 2,6-dioctadecyl-4-methyl phenol; 2,4,6-trimethyl phenol; 2,4,6-triisopropyl phenol; 2,4,6-tri-t-butyl phenol; 2-t-butyl-4,6-dimethyl phenol; 2,6-methyl-4-didodecyl phenol; Tris (3,5-di-t-butyl-4-hydroxy isocyanurate and tris (2-methyl-4-hydroxy-5-t-butylphenyl) butane.

More preferred are octadecyl-3,5-di-t-butyl-4-hydroxy hydroxycinnamate (NAUGARD 76, Uniroyal Chemical; IRGANOX 1076, CIiba-Geigy); Tetrakis {methylene (3,5-di-t-butyl-4-hydroxy-hydroxycinnamate)} methane (NAUGARD 10, Uniroyal Chemical; IRGANOX 1010, Ciba-Geigy); 1,2-bis (3,5-di-t-butyl-4-hydroxyhydrocinnamoyl) hydrazine (IRGANOX MD 1024, Ciba-Geigy); 1,3,5-tris (3,5-di-t-butyl-4-hydroxybenzyl) -s-triazine-2,4,6 (1H, 3H, 5H) trione (IRGANOX 3114, Ciba- Geigy); 1,3,5-tris (4-t-butyl-3-hydroxy-2,6-dimethylbenzyl) -s-triazine-2,4,6- (1H, 3H, 5H) trione (CYANOX 1790 , American Cyanamid Co.); 1,3,5-trimethyl-2,4,6-tris (3,5-di-t-butyl-4-hydroxybenzyl) benzene (ETHANOX 330, Ethyl Corp.); 1,3,5-tris (2-hydroxyethyl) -5-triazine-2,4,6 (1H, 3H, 5H) -trione and bis (3,3-bis (4-hydroxy-3 3,5-di-t-butyl-4-hydroxyhydrocinnamic acid triester with -t-butylphenyl) butanone acid) glycol ester.

Most preferred are hindered phenols having a molecular weight of 700 or more, in particular polyphenols having three or more substituted phenol groups, for example tetrakis {methylene (3,5-di-t-butyl-4-hydroxy-hydrocinnamate) } Methane and 1,3,5-trimethyl-2,4,6-tris (3,5-di-t-butyl-4-hydroxybenzyl) benzene.

Secondary amines useful in practicing the present invention can be represented by the following general formula:

R ^One -NH-R ²

In formula, R <^1> and R <^2> may be the same, but need not necessarily be the same. Thus, in a preferred embodiment, R ¹ and R ² contain (i) aromatic carbons, (ii) aromatic carbons connected to a second nitrogen atom to form phenylene diamine and (iii) carbon atoms connected with an oxygen atom That is, it may be independently selected from aliphatic R ¹ and R ² containing a carbonyl group.

When R ¹ is aliphatic, it may be straight or branched, for example 1 to 12 carbons such as methyl, ethyl, propyl, butyl, pentyl, hexyl, heptyl, octyl, nonyl, decyl, undecyl, dodecyl and isomers thereof It may have an atom. When R <^1> is aliphatic, it is preferable that it is a linear or branched aliphatic group which has 1-8 carbon atoms, and it is more preferable when it has 1-4 carbon atoms.

The amine antioxidant can be a hydrocarbon substituted diarylamine, such as, for example, aryl, alkyl, alkaryl, and aralkyl substituted diphenylamine antioxidant materials. Commercially available hydrocarbon substituted diphenylamines include, but are not limited to, substituted octylated, totylated, and heptylated diphenylamines and para-substituted styrenated or α-methyl styrenated diphenylamines. Sulfur-containing hydrocarbon substituted diphenylamines such as p- (p-toluenesulfonylamido) -diphenylamine are also considered part of this class.

Hydrocarbon-substituted diarylamines useful in practicing the present invention can be represented by the following general formula:

Ar-NH-Ar '

Wherein Ar and Ar 'are independently selected from aryl radicals and at least one of them is preferably substituted by one or more alkyl radicals. Aryl radicals can be, for example, phenyl, biphenyl, terphenyl, naphthyl, anthryl, phenanthryl and the like. The alkyl substituent (s) may be, for example, methyl, ethyl, propyl, butyl, pentyl, hexyl, heptyl, octyl, nonyl, decyl, isomers thereof.

Preferred hydrocarbon-substituted diarylamines are disclosed in US Pat. Nos. 3,452,056 and 3,505,225, the contents of which are incorporated herein by reference. Preferred hydrocarbon-substituted diarylamines can be represented by the following formulas:

Wherein R ₁ is selected from phenyl and p-tolyl radical;

R ₂ and R ₃ are independently selected from methyl, phenyl and p-tolyl radicals;

R ₄ is selected from methyl, phenyl, p-tolyl and neopentyl radicals;

R ₅ is selected from methyl, phenyl, p-tolyl and 2-phenylisobutyl radical;

R ₆ is methyl radical.

Wherein R ₁ to R ₅ are independently selected from the radicals shown in formula (I) and R ₇ is selected from methyl, phenyl, and p-tolyl radicals;

X is a metal salt of methyl, ethyl, C ₃ -C ₁₀ sec-alkyl, α, α-dimethylbenzyl, α-methylbenzyl, chlorine, bromine, carboxyl and carboxylic acid, where the metal is zinc, cadmium, nickel, lead Radicals selected from tin, magnesium and copper;

Y is a radical selected from hydrogen, methyl, ethyl, C ₃ -C ₁₀ sec-alkyl, chlorine and bromine.

Wherein R ₁ is selected from phenyl or p-tolyl radical;

R ₂ and R ₃ are independently selected from methyl, phenyl, and p-tolyl radicals;

R ₄ is selected from hydrogen, straight or branched chain C ₃ -C ₁₀ primary, secondary and tertiary alkyl, and C ₃ -C ₁₀ alkoxy;

X and Y are radicals selected from hydrogen, methyl, ethyl, C ₃ -C ₁₀ sec-alkyl, chlorine and bromine.

Wherein R ₉ is selected from phenyl and p-tolyl radicals;

R ₁₀ is a radical selected from methyl, phenyl, p-tolyl and 2-phenyl isobutyl;

R ₁₁ is a radical selected from methyl, phenyl, and p-tolyl.

Wherein R ₁₂ is selected from phenyl or p-tolyl radical;

R ₁₃ is selected from methyl, phenyl, and p-tolyl radical;

R ₁₄ is selected from methyl, phenyl, p-tolyl and 2-phenylisobutyl radical;

R ₁₅ is selected from hydrogen, α, α-dimethylbenzyl, α-methylbenzyl, triphenylmethyl, and α, αp-trimethylbenzyl radical.

Typical compounds useful in the present invention are as follows:

R ₉ is phenyl and R ₁₀ and R ₁₁ are methyl.

Among the preferred hydrocarbon-substituted diarylamines described above, particularly preferred are substituted diphenylamines having the following structure, wherein R ₁₆ and R ₁₇ are methyl or phenyl.

Compounds in which both R ₁₆ and R ₁₇ are methyl are 4,4'-bis (α, α-dimethylbenzyl) diphenylamine and compounds in which both R ₁₆ and R ₁₇ are phenyl are 4,4'-bis (α-methylbenzyl) diphenylamine.

The second class of amine antioxidants includes the reaction product of diarylamines with aliphatic ketones. Diarylamine aliphatic ketone reaction products useful in the present invention are described in U.S. Patent Nos. 1,906,935; 1,975,167; 2,002,642; And 2,562,802. In brief, these products react, if desired, with an aliphatic ketone, preferably acetone, in the presence of a suitable catalyst a diarylamine, preferably diphenylamine, which may have one or more substituents on either aryl group. Get by. In addition to diphenylamine, other suitable diarylamine reactants include dinaphthyl amine; p-nitrodiphenylamine; 2,4-dinitrodiphenylamine; p-aminodiphenylamine; p-hydroxydiphenylamine; Etc. are included. In addition to acetone, other useful ketone reactants include methyl ethyl ketone, diethyl ketone, monochloroacetone, dichloroacetone, and the like.

Preferred diarylamine-aliphatic ketone reaction products are obtained from condensation reactions of diphenylamine with acetone, for example according to the conditions described in US Pat. No. 2,562,802 (NAUGARD A, Uniroyal Chemical). Commercially available products are supplied as light tan-green powder or greenish brown flakes and have a melting point in the range from 85 to 95 ° C.

A third class of suitable amines are the N, N 'hydrocarbon substituted p-phenylene diamines. The hydrocarbon substituent may be an alkyl or aryl group which may be substituted or unsubstituted. As used herein, the term "alkyl" includes cycloalkyl, unless stated otherwise. Representative materials are as follows:

N-phenyl-N'-cyclohexyl-p-phenylenediamine;

N-phenyl-N'-sec-butyl-p-phenylenediamine;

N-phenyl-N'-isobutyl-p-phenylenediamine;

N-phenyl-N '-(1,3-dimethylbutyl) -p-phenylenediamine;

N, N'-bis (1,4-dimethylpentyl) -p-phenylenediamine;

N, N'-diphenyl-p-phenylenediamine;

N, N'-di-beta naphthyl-p-phenylenediamine; Mixed diaryl-p-N, N'-bis- (1-ethyl-3-methylpentyl) -p-phenylenediamine; And

N, N'-bis- (1-methylheptyl) -p-phenylenediamine.

The fourth class of amine antioxidants is based on quinoline, in particular based on polymerized 1,2-dihydro-2,2,4-trimethylquinoline (Naugard Super Q, Uniroyal Chemical). Representative materials include polymerized 2,2,4-trimethyl-1,2-dihydroquinoline; 6-dodecyl-2,2,4-trimethyl-1,2-dihydroquinoline; 6-ethoxy-2,2,4-trimethyl-1,2-dihydroquinoline and the like.

Particularly preferred secondary amines used in practicing the present invention are 4,4'-bis (ω, ωdimethyl) diphenylamine (Naugard 445, Uniroyal Chemical), octylated diphenylamine (Naugard Octamine, Uniroyal Chemical), and N-phenyl-N '-(p-toluenesulfonyl) -p-phenylene diamine (Naugard SA, Uniroyal Chemical).

As an alternative to, or in addition to, the aforementioned secondary amines, it is possible to use substances based on N, N′-substituted oxamides, preferably having hindered phenol functionality. Particularly preferred classes of compounds are 2,2'-oxamido-bis {ethyl-3- (3,5-di-t-butyl-4-hydroxyphenyl)} propionate (Naugard XL-1, Uniroyal Chemical) )to be.

Thioethers useful in practicing the present invention may have the following structure:

Wherein p is 1 or 2, q is 0 or 1, p + q is 2, R ₁₈ is a linear or branched alkyl moiety of 1 to 20 carbon atoms, and R ₁₉ is a straight chain of 1 to 8 carbon atoms Or branched alkylene moieties. Thus, R ₁₈ is for example methyl, ethyl, propyl, butyl, pentyl, hexyl, heptyl, octyl, nonyl, decyl, undecyl, dodecyl, tridecyl, tetradecyl, pentadecyl, hexadecyl, heptadecyl, octadecyl, Nonadecyl, eicosyl and isomers thereof; R ₁₉ may be for example methylene, ethylene, propylene, butylene, pentylene, hexylene, heptylene, octylene and isomers thereof. It is preferred that R ₁₈ is an alkyl moiety of straight or branched chain of 8 to 18 carbon atoms and R ₁₉ is an alkylene moiety of straight or branched chain of 1 to 4 carbon atoms. More preferably, R ₁₉ is ethylene, ie, —CH ₂ —CH ₂ —.

Other thioethers useful for practicing the present invention can be represented by the following structural formula:

Wherein a is 0 to 3, b is 1 to 4 and a + b is 4, R ₁₈ is as defined above, and R ₁₉ and R ₂₀ are each a straight or branched chain alkylene moiety of 1 to 8 carbon atoms, respectively. to be. It is preferred that R ₁₉ and R ₂₀ are independently alkylene moieties of the straight or branched chain of 1 to 4 carbon atoms. More preferably, R ₂₀ is methylene, i.e., -CH ₂ -, and, R ₁₉ is ethylene, i.e., - CH ₂ -CH ₂ - may be a.

Examples of preferred thioethers useful in practicing the present invention are distearylthiodipropionate (Mark DSTDP, Witco Corp.), dilaurylthiodipropionate (Mark DLTDP, Witco Corp.), pentaerythritol tetra Products such as Keith (β-laurylthiopropionate) (Seenox 412S, Witco Corp.), and pentaerythritol octylthiopropionate (Mark 2140, Witco Corp.).

The sum of the amine / oxamide derivative (s), hindered phenol (s), and thioether (s) incorporated into the thermoplastic resin of the present invention, which may include glass and / or carbon black, is at least oxidative. It will be the amount required to give a significant level of stability to degradation. Generally, such amounts can range from about 0.01 to about 10.0 weight percent, preferably from about 0.5 to about 5 weight percent, relative to the thermoplastic resin mixture. Antioxidant binding amounts may be used in amounts exceeding about 10% by weight, but such amounts can adversely affect the physical and mechanical properties of the polymerizable substrate, in which case they should usually be avoided.

The relative ratio of hindered phenol to secondary amine / N, N′-substituted oxamide to thioether can vary greatly. In general, the ratio of hindered phenol to secondary amine / oxamide may range from about 20: 1 to about 1:20, preferably from about 10: 1 to about 1:10. Likewise, the ratio of secondary amine / oxamide to thioether may range from about 20: 1 to about 1:20, preferably from about 10: 1 to about 1:10. Preferable results can also be obtained by using a ratio above or below the broader range.

As mentioned above, antioxidants having both functional groups, secondary amine / oxamides and hindered phenol functional groups, can be used to practice the present invention. In this case, such bifunctional antioxidants may take the place of secondary amines / antioxidants of the invention or hindered phenols of the invention, but not both. Thus, the ratios described in the paragraphs above still apply.

Glass may be present in the thermoplastic resin used to practice the present invention in an amount of up to about 50% by weight relative to the weight of the thermoplastic resin. Preferably, when glass is present, it is preferably present in an amount of about 5 to about 50 weight percent, more preferably about 20 to about 40 weight percent.

Carbon blacks may be present in the thermoplastic resins of the present invention and are preferably present, the amount of which is about 10% by weight or less of the thermoplastic resin. It is preferably present in an amount of about 0.01 to about 10 weight percent, more preferably about 0.1 to about 5 weight percent.

The process used to incorporate the amine / oxamide derivative (s), hindered phenol (s), and thioether (s) into the thermoplastic resin is generally not of great importance, and any known method used to incorporate additives into such resins is known. You may use a process. For example, these materials are introduced into the thermoplastic resin as a premix, or maintained separately and then added simultaneously or subsequently to the resin and then distributed homogeneously into the polymer by milling, extrusion mixing, or other mechanical work processes. Can be introduced. Either one of the first, second or third stabilizers, or both, or all three, are added to the thermoplastic resin in such a way as to include it in a preconcentrate or delivery system such as a suitable solvent or cosolvent. You can.

According to conventional methods, other additives may also be introduced into the resin prior to, during, and / or after addition of the antioxidant. Such additives include other stabilizers, colorants, reinforcing agents, fillers, antistatic agents, lubricants, plasticizers, and the like, and are introduced in conventional amounts.

Various features and aspects of the present invention will be described in more detail with reference to the following examples. These examples are presented to show those skilled in the art how to practice the present invention within the scope of the present invention, and in any way, the scope of the present invention is not limited to these examples.

Oxidative induction time

Circular discs were cut from a 0.25 mm film of material to be tested and placed in an aluminum pan for use in a Perkin-Elmer DSC-2C differential scanning calorimeter (DSC). During conditioning, the test chamber of the DSC calorimeter is purged with nitrogen, for example to an isocratic temperature of 200 ° C., and then immediately replaced with oxygen at a flow rate of 20 cc ′ per minute to induce thermal oxidative degradation. Oxidative induction time (OIT) is the time span in minutes between when the oxygen environment is introduced to reach the compositional temperature and when DSC detects the onset of oxidation.

Thermogravimetric analysis (TGA)

TGA was performed on a 20 mil polypropylene film using a TA-High Resolution TGA 2950 instrument. Samples were prepared by dieing out a 1/8 inch diameter disc. The sample was weighed and then heated to 230 ° C. under nitrogen. After equilibration, the gas flow was turned to air and performed isothermally at 230 ° C. for 120 minutes. All graphs were analyzed using TA software for the time point when 2% weight loss occurred relative to the weight before heating.

Molding of Polypropylene Films

A dry mixture was made from Profax 6501 (Montel) polypropylene. All compositions contained 0.1% calcium stearate (Witco Corp.). Printex-60 (Degussa) was used as a material containing carbon black. After adding the stabilizer to polypropylene in the amounts indicated in the examples, the resulting dry mixture was mixed for 15 minutes at 185 ° C., 15 r.p.m., in a Brabender C.E.O-6 type measuring head. The resulting product was used for press molding of a 6 x 6 "film at 380 ° F. for 4 minutes. 10 mil thick films were used for OIT measurements and 20 mil test specimens were mainly used for long term thermal aging, TGA and weight loss testing. It was.

Glass Mat Reinforced Polypropylene

A 20 mil polypropylene film was made from Fina 3882 (MFI = 100) material using the additives disclosed in the following examples. All compositions contained 0.1% calcium stearate (Witco) and 0.9% Printex 60 (Degussa). ecoMat G-500 glass filament products (Sculler, Germany) were used to stack two 6 x 3 "polypropylene films alternately with glass mats with a single needle of the same size to make a total of six layers of sandwich. Two sandwiches were joined by sandwiching them, and then they were press molded for 3 minutes at 380 ° F. After cooling, the resulting composite was placed in a circulating air oven at 230 ° C. for 90 seconds, followed by weight loss at 150 ° C. and 230 ° C. This glass-filled test specimen was used to test.

Long term heat aging and weight loss test

Long-term heat aging (LTHA) and weight loss tests were performed using a circulating air oven (Blue M) at the temperatures specified in the following examples. LTHA test specimens were visually inspected for 24 hour intervals. For the weight loss test, the test specimens were removed from the oven, cooled in a desiccator and then weighed.

Example 1-23

These examples illustrate the long term thermal aging behavior of a 20 mil polypropylene film at 150 ° C. All compositions contained 0.9% carbon black and 0.1% stearate.

Example 24-36

These examples show the OIT value of a 10 mil polypropylene film at 200 ° C. All compositions contained 0.9% carbon black and 0.1% calcium stearate.

Example 37-41

These examples illustrate the weight loss over time of a 20 mil polypropylene film at 150 ° C. All compositions contained 0.9% carbon black and 0.1% calcium stearate.

Example 42-61

These examples describe the thermogravimetric analysis of a 20 mil polypropylene film at 230 ° C. All compositions contained 0.9% carbon black and 0.1% calcium stearate.

Example 62-65

Glass Mat Reinforced Polypropylene

These examples illustrate the weight loss over time at 150 ° C. of a polypropylene film reinforced with 30% (by weight) glass. All compositions contained 0.9% carbon black and 0.1% calcium stearate (relative to polypropylene). The weight percentages of the A, B, and C components listed in Examples 62-65 are relative to polypropylene.

Example 66-70

Glass Mat Reinforced Polypropylene

These examples illustrate the weight loss over time at 230 ° C. of a polypropylene film reinforced with 30% (by weight) glass. All compositions contained 0.9% carbon black and 0.1% calcium stearate (relative to polypropylene). The weight percentages of the A, B and C components listed in Examples 66-70 are relative to polypropylene.

Example 71-72

These examples illustrate long term thermal aging at 150 ° C. of a 10 mil polypropylene film that does not contain carbon black. All compositions contained 0.1% calcium stearate.

Example 73-74

These examples illustrate OIT values at 200 ° C. of a 10 mil polypropylene film that does not contain carbon black. All compositions contained 0.1% calcium stearate.

According to the above examples, addition of 0.3% DSTDP to the mixture of Naugard 10 and Naugard 445 (Examples 5 and 6) showed that oven aging increased 3.5 times from 192 hours to 678 hours. In addition, for Seenox 412S, as can be seen in Example 7, it was increased to 846 hours and recorded 4.5 times better. Similar synergies and unexpected results were observed for Naugard Octamine and Naugard SA as evidenced by Examples 17-20.

Addition of 0.3% thioether to the mixture of Naugard 10 and Super Q showed that the oven aging measured to breakdown only doubled to a correspondingly -440 hours-until the breakdown. Thus, the secondary amines of the quinoline type represented by Naugard Super Q of Examples 21 and 22, although within the scope of the present invention, have large oven aging, given the time (time) measurements until breakdown. Not so desirable because it did not improve. On the other hand, Examples 21 and 22 further show the unexpected synergistic effect obtained when thioether is added to a mixture of hindered phenols and secondary amines.

Example 23 is intended to show the stabilizing effect of a three-component mixture consisting of both N, N'-substituted oxamido functional groups and phenolic functional groups, those having secondary amine functional groups and thioether groups. In addition, when tested for glass, Naugard 445 or Naugard XL-1 as a secondary amine component or as N, N'-substituted oxamido component, Naugard 10 as hindered phenol component, and DSTDP or Seenox 412S as thioether component, respectively Testing the mixture containing (Examples 62-65) for weight loss at 150 ° C. yielded consistently much better protection against GMT test specimens as compared to the control, as seen from the weight loss measurements. For example, the control showed a weight loss of 10.4%, while the mixture of Naugard 445, Naugard 10, and DSTDP (Example 64) only showed a weight loss of 2.5%.

Finally, for the weight loss test at 230 ° C. for the glass, the mixture of secondary amine / N, N′-substituted oxamides, hindered phenols and thioethers weighed less than 2% by weight after 15 minutes at 230 ° C. Not only did it meet the requirements of the GMT industry, which allowed only losses, it consistently outperformed the control (Examples 66-70).

As many variations and modifications can be made to the invention without departing from the principles of the invention, it is to be understood that the protection scope of the invention is defined by the appended claims.

Claims (56)

(A) thermoplastic resin; And (B) A composition comprising at least one sterically hindered phenol antioxidant, at least one secondary amine antioxidant and / or at least one N, N'-substituted oxamide, and at least one thioether antioxidant. The composition of claim 1 further comprising carbon black. The composition of claim 1 further comprising glass. The composition of claim 2 further comprising glass. (A) thermoplastic resin; (B) up to 10% by weight carbon black; (C) up to 50% glass; And (D) Stabilization amount of following (1)-(3) (1) at least one member selected from the group consisting of With N, N'-substituted oxamides and / or one or more secondary amine antioxidants A first stabilizer made up; (Iii) hydrocarbon-substituted diarylamines, (Ii) reaction products of diarylamines and aliphatic ketones, (Iii) N, N'-hydrocarbon substituted para-phenylenediamine, and (Iii) polymerized dihydroquinoline; (2) second stabilization consisting of one or more sterically hindered phenolic antioxidants My; And (3) A composition comprising a third stabilizer consisting of at least one thioether antioxidant. 6. The thermoplastic resin of claim 5 wherein the thermoplastic resin is polyethylene, polypropylene, polyisobutylene, polymethylbutene-1, polymethylpentene-1, polybutene-1, polyisobutylene, ethylene-propylene having a majority of propylene. Copolymers, propylene-butene-1 copolymers, propylene-isobutylene copolymers, polystyrenes, polyvinyl halides, polyamides, polyesters, polyphenylene oxides, polyphenylene sulfides, polyacetals, aliphatic polyketone copolymers or The composition is selected from the group consisting of terpolymer, poly (ethersulfone), polycarbonate, liquid crystal polymer, poly (ether ether ketone) and poly (arylate). 6. The composition of claim 5, wherein said first stabilizer is a hydrocarbon-substituted diarylamine. 8. The composition of claim 7, wherein the hydrocarbon-substituted diarylamine is 4,4'-bis (α, α-dimethylbenzyl) diphenylamine. 8. The composition of claim 7, wherein the hydrocarbon-substituted diarylamine is 4,4'-bis (α-methylbenzyl) diphenylamine. 6. The composition of claim 5, wherein said first stabilizer is a reaction product of a diarylamine and an aliphatic ketone. The composition of claim 10, wherein said diarylamine is diphenylamine. The composition of claim 10, wherein the ketone is acetone. 6. The composition of claim 5, wherein said first stabilizer is N, N'-hydrocarbon-substituted para-phenylene diamine. The method of claim 13, wherein the N, N'-hydrocarbon-substituted para-phenylene diamine is selected from the group consisting of N-phenyl-N'-cyclohexyl-p-phenylenediamine; N-phenyl-N'-sec-butyl-p-phenylenediamine; N-phenyl-N'-isopropyl-p-phenylenediamine; N-phenyl-N '-(1,3-dimethylbutyl) -p-phenylenediamine; N, N'-diphenyl-p-phenylenediamine; N, N'-bis- (1,4-dimethylpentyl) -p-phenylenediamine; N, N'-di-beta naphthyl-p-phenylenediamine; Mixed diaryl-p-N, N'-bis- (1-ethyl-3-methylpentyl) -p-phenylenediamine; And N, N'-bis- (1 methylheptyl) -p-phenylenediamine. 6. The composition of claim 5, wherein said first stabilizer is polymerized dihydroquinoline. The method of claim 15, wherein the polymerized dihydroquinoline is polymerized 2,2,4-trimethyl-1,2-dihydroquinoline; 6-dodecyl-2,2,4-trimethyl-1,2-dihydroquinoline; And 6-ethoxy-2,2,4-trimethyl-1-2-dihydroquinoline. 6. The composition of claim 5, wherein said first stabilizer is N, N'-substituted oxamide. 18. The method of claim 17, wherein the N, N'-substituted oxamide is 2,2'-oxamido-bis {ethyl-3- (3,5-di-t-butyl-4-hydroxyphenyl)} prop A composition that is cypionate. 6. The composition of claim 5, wherein the sterically hindered phenol has a molecular weight of at least 500 Da. 20. The composition of claim 19, wherein the sterically hindered phenol has a molecular weight of at least 700 Da. The method of claim 5, wherein the hindered phenol, 1,2-bis (3,5-di-t-butyl-4-hydroxyhydrocinnamoyl) hydrazine; 1,3,5-trimethyl-2,4,6-tris (3,5-di-t-butyl-4-hydroxybenzyl) benzene; 1,3,5-tris (3,5-di-t-butyl-4-hydroxybenzyl) -s-triazine-2,4,6 (1H, 3H, 5H) trione; 1,3,5-tris (4-t-butyl-3-hydroxy-2,6-dimethylbenzyl) -s-triazine-2,4,6- (1H, 3H, 5H) trione; 2-t-butyl-4,6-dimethyl phenol; 2,2'-methylenebis (4-ethyl-6-t-butyl-phenol); 2,2'-methylenebis (4-methyl-6-t-butyl phenol); 2,4-dimethyl-6-octyl-phenol; 2,4-dimethyl-6-t-butyl phenol; 2,4,6-tri-t-butyl phenol; 2,4,6-triisopropyl phenol; 2,4,6-trimethyl phenol; 2,6-di-t-butyl-4-ethyl phenol; 2,6-di-t-butyl-4-methyl phenol; 2,6-di-t-butyl-4-n-butyl phenol 2,6-dioctadecyl-4-methyl phenol; 2,6-methyl-4-didodecyl phenol; 1,3,5-tris (2-hydroxyethyl) -5-triazine-2,4,6 (1H, 3H, 5H) -trione; 3,5-di-t-butyl-4-hydroxyhydrocinnamic acid tryster having a bis (3,3-bis (4-hydroxy-3-t-butylphenyl) butanoic acid) glycol ester; 4-hydroxymethyl-2,6-di-t-butyl phenol; Tetrakis {methylene (3,5-di-t-butyl-4-hydroxy-hydrocinnamate)} methane; And The composition is selected from the group consisting of 1,3,5-trimethyl-2,4,6-tris (3,5-di-t-butyl-4-hydroxybenzyl) benzene The composition of claim 21, wherein the sterically hindered phenol is tetrakis {methylene (3,5-di-t-butyl-4-hydroxy-hydrocinnamate)} methane. The composition of claim 21, wherein the sterically hindered phenol is 1,3,5-trimethyl-2,4,6-tris (3,5-di-t-butyl-4-hydroxybenzyl) benzene. 6. The composition of claim 5, wherein the thioether is selected from the following structures. And Wherein p is 1 or 2, q is 0 or 1, p + q is 2, a is 0 to 3, b is 1 to 4, a + b is 4 and R ₁₈ is carbon atom 1 Straight or branched chain alkyl moieties having from 20 to 20, and R ₁₉ and R ₂₀ are selected from straight or branched chain alkylene moieties having from 1 to 8 carbon atoms, respectively. 25. The composition of claim 24, wherein said thioether is distearylthiodipropionate. The composition of claim 24 wherein said thioether is dilaurylthiodipropionate. The composition of claim 24, wherein the thioether is pentaerythritol tetrakis (β-laurylthiopropionate). 25. The composition of claim 24, wherein the thioether is pentaerythritol octylthiopropionate. At least one sterically hindered phenolic antioxidant, at least one secondary amine antioxidant and / or at least one N, N'-substituted oxamide antioxidant, and at least one thioether antioxidant in a composition comprising a thermoplastic resin The stabilization method of the composition containing the thermoplastic resin which consists of adding the stabilization amount of this. The method of claim 29, wherein the composition further comprises carbon black. The method of claim 29, wherein said composition further comprises glass. 31. The method of claim 30, wherein said composition further comprises glass. (A) at least one N, N'-substituted selected from the group consisting of the following (1) to (4) Oxamide antioxidant and / or one or more secondary amine antioxidants Gin first stabilizer; (1) hydrocarbon-substituted diarylamines, (2) reaction products of diarylamines and aliphatic ketones, (3) N, N'-hydrocarbon substituted para-phenylenediamine, and (4) polymerized dihydroquinoline; (B) a second stabilizer consisting of at least one hindered phenol antioxidant; And (C) a thermoplastic resin consisting of adding a stabilizing amount of a third stabilizer consisting of at least one thioether antioxidant to a composition comprising a thermoplastic resin, up to 10 weight percent carbon black, and up to 50 weight percent glass, A method of stabilizing a composition comprising up to 10 weight percent carbon black, and up to 50 weight percent glass. 34. The ethylene-propylene copolymer of claim 33 wherein the thermoplastic resin is predominantly polyethylene, polypropylene, polyisobutylene, polymethylbutene-1, polymethylpentene-1, polybutene-1, polyisobutylene, propylene. Polymers, propylene-butene-1 copolymers, propylene-isobutylene copolymers, polystyrenes, polyvinyl halides, polyamides, polyesters, polyphenylene oxides, polyphenylenesulfides, polyacetals, aliphatic polyketone copolymers or tertiary Stabilizing method selected from the group consisting of polymer, poly (ethersulfone), polycarbonate, liquid crystal polymer, poly (etheretherketone) and poly (arylate). 34. The method of claim 33, wherein said first stabilizer is a hydrocarbon-substituted diarylamine. 36. The method of claim 35, wherein said hydrocarbon-substituted diarylamine is 4,4'-bis (α, α-dimethylbenzyl) diphenylamine. 36. The method of claim 35, wherein said hydrocarbon-substituted diarylamine is 4,4'-bis (α-methylbenzyl) diphenylamine. 34. The method of claim 33, wherein said first stabilizer is a reaction product of a diarylamine and an aliphatic ketone. The method of claim 38, wherein said diarylamine is diphenylamine. 39. The method of claim 38, wherein said ketone is acetone. 34. The method of claim 33, wherein said first stabilizer is N, N'-hydrocarbon-substituted para-phenylene diamine. 42. The method of claim 41, wherein the N, N'-hydrocarbon-substituted para-phenylene diamine is selected from the group consisting of N-phenyl-N'-cyclohexyl-p-phenylenediamine; N-phenyl-N'-sec-butyl-p-phenylenediamine; N-phenyl-N'-isopropyl-p-phenylenediamine; N-phenyl-N '-(1,3-dimethylbutyl) -p-phenylenediamine; N, N'-diphenyl-p-phenylenediamine; N, N'-bis- (1,4-dimethylpentyl) -p-phenylenediamine; N, N'-di-beta naphthyl-p-phenylenediamine; Mixed diaryl-p-N, N'-bis- (1-ethyl-3-methylpentyl) -p-phenylenediamine; And N, N'-bis- (1 methylheptyl) -p-phenylenediamine. 34. The method of claim 33, wherein said first stabilizer is polymerized dihydroquinoline. 44. The method of claim 43, wherein the polymerized dihydroquinoline is polymerized 2,2,4-trimethyl-1,2-dihydroquinoline; 6-dodecyl-2,2,4-trimethyl-1,2-dihydroquinoline; And 6-ethoxy-2,2,4-trimethyl-1-2-dihydroquinoline. 34. The method of claim 33, wherein said first stabilizer is N, N'-substituted oxamide. 46. The method of claim 45, wherein the N, N'-substituted oxamide is 2,2'-oxamido-bis {ethyl-3- (3,5-di-t-butyl-4-hydroxyphenyl)} prop. Stabilization method that is cypionate. 34. The method of claim 33, wherein said hindered phenol has a molecular weight of at least 500 Da. 48. The method of claim 47, wherein said hindered phenol has a molecular weight of at least 700 Da. The method of claim 33, wherein the hindered phenol is 1,2-bis (3,5-di-t-butyl-4-hydroxyhydrocinnamoyl) hydrazine; 1,3,5-trimethyl-2,4,6-tris (3,5-di-t-butyl-4-hydroxybenzyl) benzene; 1,3,5-tris (3,5-di-t-butyl-4-hydroxybenzyl) -s-triazine-2,4,6 (1H, 3H, 5H) trione; 1,3,5-tris (4-t-butyl-3-hydroxy-2,6-dimethylbenzyl) -s-triazine-2,4,6- (1H, 3H, 5H) trione; 2-t-butyl-4,6-dimethyl phenol; 2,2'-methylenebis (4-ethyl-6-t-butyl-phenol); 2,2'-methylenebis (4-methyl-6-t-butyl phenol); 2,4-dimethyl-6-octyl-phenol; 2,4-dimethyl-6-t-butyl phenol; 2,4,6-tri-t-butyl phenol; 2,4,6-triisopropyl phenol; 2,4,6-trimethyl phenol; 2,6-di-t-butyl-4-ethyl phenol; 2,6-di-t-butyl-4-methyl phenol; 2,6-di-t-butyl-4-n-butyl phenol 2,6-dioctadecyl-4-methyl phenol; 2,6-methyl-4-didodecyl phenol; 1,3,5-tris (2-hydroxyethyl) -5-triazine-2,4,6 (1H, 3H, 5H) -trione; 3,5-di-t-butyl-4-hydroxyhydrocinnamic acid tryster having a bis (3,3-bis (4-hydroxy-3-t-butylphenyl) butanoic acid) glycol ester; 4-hydroxymethyl-2,6-di-t-butyl phenol; Tetrakis {methylene (3,5-di-t-butyl-4-hydroxy-hydrocinnamate)} methane; And The stabilization method is selected from the group consisting of 1,3,5--trimethyl-2,4,6-tris (3,5-di-t-butyl-4-hydroxybenzyl) benzene. 50. The method of claim 49, wherein the sterically hindered phenol is tetrakis {methylene (3,5-di-t-butyl-4-hydroxy-hydrocinnamate)} methane. 50. The method of claim 49, wherein the sterically hindered phenol is 1,3,5-trimethyl-2,4,6-tris (3,5-di-t-butyl-4-hydroxybenzyl) benzene. 34. The method of claim 33, wherein said thioether is selected from the following structures. And Wherein p is 1 or 2, q is 0 or 1, p + q is 2, a is 0 to 3, b is 1 to 4, a + b is 4 and R ₁₈ is carbon atom 1 Straight or branched chain alkyl moieties having from 20 to 20, and R ₁₉ and R ₂₀ are selected from straight or branched chain alkylene moieties having from 1 to 8 carbon atoms, respectively. 53. The method of claim 52, wherein said thioether is distearylthiodipropionate. 53. The method of claim 52, wherein said thioether is dilaurylthiodipropionate. The method of claim 52, wherein the thioether is pentaerythritol tetrakis (β-laurylthiopropionate). 53. The method of claim 52, wherein said thioether is pentaerythritol octylthiopropionate.